Magnetostratigraphy of the late Cenozoic Laojunmiao anticline in the northern Qilian Mountains and its implications for the northern Tibetan Plateau uplift  

作　　者：FANG Xiaomin1,2, ZHAO Zhijun3,2, LI Jijun2, YAN Maodu2, PAN Baotian2, SONG Chunhui2 & DAI Shuang2 1. Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China 2. Key Laboratory of Western China’s Environmental Systems, Ministry of Education & College of Resources and Environment, Lanzhou University, Lanzhou 730000, China 3. College of Geography, Nanjing Normal University, Nanjing 210097, China 

出　　处：《Science China Earth Sciences》2005年第7期1040-1051,共12页中国科学（地球科学英文版）

基　　金：the NSFC(Grant No.40334038,40121303);the National Key Project for Basic Research on the Tibetan Plateau(Grant No.G1998040809);CAS"Hundred Talents Project"(Grant No.Ren-Jiao-Zi[2000]02821.

摘　　要：Cenozoic sediments in the foreland basin--Jiuquan Basin in west Hexi Corridor recorded tectonic uplift information of the Qilian Mountains. High resolution paleomagnetic dating of the Laojunmiao (LJM) section across the central LJM anticline in the southern Jiuquan Basin reveals ages of the Getanggou Member, Niugetao Member in the Shulehe Formation, the Yumen Conglomerate, Jiuquan Conglomerate and Gobi Formation at >13-8.3 Ma, 8.3-4.9 Ma, 3.66-0.93 Ma, 0.84-0.14 Ma and 0.14-0 Ma, respectively. Sedimentary evolution study suggests that the Qilian Mountains should begin to rise gradually since ～8-6.6 Ma, accompanied by sedimentary environments changing from lacustrine mudstones-sandstones to alluvial conglomerates. Rapid uplift of the Qilian Mountains began at ～3.66 Ma, followed by a series of stepwise or intermittent intensive uplifts at about <1.8-1.23 Ma, 0.93-0.84 Ma and 0.14 Ma, which finally resulted in the present high Qilian Mountains.Cenozoic sediments in the foreland basin——Jiuquan Basin in west Hexi Corridor recorded tectonic uplift information of the Qilian Mountains. High resolution paleomagnetic dating of the Laojunmiao (LJM) section across the central LJM anticline in the southern Jiuquan Basin reveals ages of the Getanggou Member, Niugetao Member in the Shulehe Formation, the Yumen Conglomerate, Jiuquan Conglomerate and Gobi Formation at >13―8.3 Ma, 8.3―4.9 Ma, 3.66― 0.93 Ma, 0.84―0.14 Ma and 0.14―0 Ma, respectively. Sedimentary evolution study suggests that the Qilian Mountains should begin to rise gradually since ~8―6.6 Ma, accompanied by sedimentary environments changing from lacustrine mudstones-sandstones to alluvial conglom- erates. Rapid uplift of the Qilian Mountains began at ~3.66 Ma, followed by a series of stepwise or intermittent intensive uplifts at about <1.8―1.23 Ma, 0.93―0.84 Ma and 0.14 Ma, which finally resulted in the present high Qilian Mountains.

关 键 词：QILIAN Mountains Qinghai-Tibetan Plateau Jiuquan Basin magnetostratigraphy. 

分 类 号：P542.1[天文地球—构造地质学]